Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe.

BACKGROUND AND AIMS: Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC. METHODS: This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed. RESULTS: One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans. CONCLUSIONS: North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Lifetime exercise dose and ventricular arrhythmias in patients with mitral valve prolapse.

AIMS: Patients with mitral valve prolapse (MVP) have high risk of life-threatening ventricular arrhythmias (VAs). Data on the impact of exercise on arrhythmic risk in these patients are lacking. We explored whether lifetime exercise dose was associated with severe VA and with established risk factors in patients with MVP. Furthermore, we explored the circumstances at the VA event. METHODS AND RESULTS: In this retrospective cohort study, we included patients with MVP and assessed lifetime exercise dose as metabolic equivalents of task (MET) hours/week. Severe VA was defined as sustained ventricular tachycardia or fibrillation, aborted cardiac arrest, and appropriate shock by a primary preventive implantable cardioverter defibrillator. We included 136 MVP patients (48 years [interquartile range (IQR) 35-59], 61% female), and 17 (13%) had previous severe VA. The lifetime exercise dose did not differ in patients with and without severe VA (17 MET h/week [IQR 9-27] vs. 14 MET h/week [IQR 6-31], P = 0.34). Lifetime exercise dose > 9.6 MET h/week was a borderline significant marker for severe VA (OR 3.38, 95% CI 0.92-12.40, P = 0.07), while not when adjusted for age (OR 2.63, 95% CI 0.66-10.56, P = 0.17). Ventricular arrhythmia events occurred most frequently during wakeful rest (53%), followed by exercise (29%) and sleep (12%). CONCLUSION: We found no clear association between moderate lifetime exercise dose and severe VA in patients with MVP. We cannot exclude an upper threshold for safe levels of exercise. Further studies are needed to explore exercise and risk of severe VA.

The added value of abnormal regional myocardial function for risk prediction in arrhythmogenic right ventricular cardiomyopathy.

AIMS: A risk calculator for individualized prediction of first-time sustained ventricular arrhythmia (VA) in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients has recently been developed and validated (www.ARVCrisk.com). This study aimed to investigate whether regional functional abnormalities, measured by echocardiographic deformation imaging, can provide additional prognostic value. METHODS AND RESULTS: From two referral centres, 150 consecutive patients with a definite ARVC diagnosis, no prior sustained VA, and an echocardiogram suitable for deformation analysis were included (aged 41 ± 17 years, 50% female). During a median follow-up of 6.3 (interquartile range 3.1-9.8) years, 37 (25%) experienced a first-time sustained VA. All tested left and right ventricular (LV and RV) deformation parameters were univariate predictors for first-time VA. While LV function did not add predictive value in multivariate analysis, two RV deformation parameters did; RV free wall longitudinal strain and regional RV deformation patterns remained independent predictors after adjusting for the calculator-predicted risk [hazard ratio 1.07 (95% CI 1.02-1.11); P = 0.004 and 4.45 (95% CI 1.07-18.57); P = 0.040, respectively] and improved its discriminative value (from C-statistic 0.78 to 0.82 in both; Akaike information criterion change > 2). Importantly, all patients who experienced VA within 5 years from the echocardiographic assessment had abnormal regional RV deformation patterns at baseline. CONCLUSIONS: This study showed that regional functional abnormalities measured by echocardiographic deformation imaging can further refine personalized arrhythmic risk prediction when added to the ARVC risk calculator. The excellent negative predictive value of normal RV deformation could support clinicians considering the timing of implantable cardioverter defibrillator implantation in patients with intermediate arrhythmic risk.

Timing of cardioverter-defibrillator implantation in patients with cardiac laminopathies-External validation of the LMNA-risk ventricular tachyarrhythmia calculator.

BACKGROUND: LMNA genotype-positive patients have high risk of experiencing life-threatening ventricular tachyarrhythmias (VTAs). The LMNA-risk VTA calculator published in 2019 has not been externally validated. OBJECTIVE: The purpose of this study was to validate the LMNA-risk VTA calculator. METHODS: We included LMNA genotype-positive patients without previous VTAs from 2 large Scandinavian centers. Patients underwent electrocardiography, 24-hour Holter monitoring, and echocardiographic examinations at baseline and repeatedly during follow-up. Validation of the LMNA-risk VTA calculator was performed using Harrell's C-statistic derived from multivariable Cox regression analysis. RESULTS: We included 118 patients (age 37 years [IQR 27-49 years]; 39 [33%] probands; 65 [55%] women; 100 [85%] with non-missense LMNA variants). Twenty-three patients (19%) experienced VTA during 6.1 years (interquartile range 3.0-9.1 years) follow-up, resulting in 3.0% (95% confidence interval 2.0%-4.5%) yearly incidence rate. Atrioventricular block and reduced left ventricular ejection fraction were independent predictors of VTAs, while nonsustained ventricular tachycardia, male sex, and non-missense LMNA variants were not. The LMNA-risk VTA calculator showed 83% sensitivity and 26% specificity for identifying patients with VTAs during the coming 5 years, and a Harrell's C-statistic of 0.85, when applying ≥7% predicted 5-year VTA risk as threshold. The sensitivity increased to 100% when reevaluating risk at the time of last consultation before VTA. The calculator overestimated arrhythmic risk in patients with mild and moderate phenotype, particularly in men. CONCLUSION: Validation of the LMNA-risk VTA calculator showed high sensitivity for subsequent VTAs, but overestimated arrhythmic risk when using ≥7% predicted 5-year risk as threshold. Frequent reevaluation of risk was necessary to maintain the sensitivity of the model.

Disease progression rate is a strong predictor of ventricular arrhythmias in patients with cardiac laminopathies: a primary prevention cohort study.

AIMS: Cardiac disease progression prior to first ventricular arrhythmia (VA) in LMNA genotype-positive patients is not described. METHODS AND RESULTS: We performed a primary prevention cohort study, including consecutive LMNA genotype-positive patients from our centre. Patients underwent repeated clinical, electrocardiographic, and echocardiographic examinations. Electrocardiographic and echocardiographic disease progression as a predictor of first-time VA was evaluated by generalized estimation equation analyses. Threshold values at transition to an arrhythmic phenotype were assessed by threshold regression analyses. We included 94 LMNA genotype-positive patients without previous VA (age 38 ± 15 years, 32% probands, 53% females). Nineteen (20%) patients experienced VA during 4.6 (interquartile range 2.1-7.3) years follow up, at mean age 50 ± 11 years. We analysed 536 echocardiographic and 261 electrocardiogram examinations. Individual patient disease progression was associated with VA [left ventricular ejection fraction (LVEF) odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2-1.6 per 5% reduction, left ventricular end-diastolic volume index (LVEDVi) OR 1.2 (95% CI 1.1-1.3) per 5 mL/m2 increase, PR interval OR 1.2 (95% CI 1.1-1.4) per 10 ms increase]. Threshold values for transition to an arrhythmic phenotype were LVEF 44%, LVEDVi 77 mL/m2, and PR interval 280 ms. CONCLUSIONS: Incidence of first-time VA was 20% during 4.6 years follow up in LMNA genotype-positive patients. Individual patient disease progression by ECG and echocardiography were strong predictors of VA, indicating that disease progression rate may have additional value to absolute measurements when considering primary preventive ICD. Threshold values of LVEF <44%, LVEDVi >77 mL/m2, and PR interval >280 ms indicated transition to a more arrhythmogenic phenotype.

Highly malignant disease in childhood-onset arrhythmogenic right ventricular cardiomyopathy.

AIMS: This study aimed to explore the incidence of severe cardiac events in paediatric arrhythmogenic right ventricular cardiomyopathy (ARVC) patients and ARVC penetrance in paediatric relatives. Furthermore, the phenotype in childhood-onset ARVC was described. METHODS: Consecutive ARVC paediatric patients and genotype positive relatives ≤18 years of age were followed with electrocardiographic, structural, and arrhythmic characteristics according to the 2010 revised Task Force Criteria. Penetrance of ARVC disease was defined as fulfilling definite ARVC criteria and severe cardiac events were defined as cardiac death, heart transplantation (HTx) or severe ventricular arrhythmias. Childhood-onset disease was defined as meeting definite ARVC criteria ≤12 years of age. RESULTS: Among 62 individuals [age 9.8 (5.0-14.0) years, 11 probands], 20 (32%) fulfilled definite ARVC diagnosis, of which 8 (40%) had childhood-onset disease. The incidence of severe cardiac events was 23% (n = 14) by last follow-up and half of them occurred in patients ≤12 years of age. Among the eight patients with childhood-onset disease, five had biventricular involvement needing HTx and three had severe arrhythmic events. Among the 51 relatives, 6% (n = 3) met definite ARVC criteria at time of genetic diagnosis, increasing to 18% (n = 9) at end of follow-up. CONCLUSIONS: In a paediatric ARVC cohort, there was a high incidence of severe cardiac events and half of them occurred in children ≤12 years of age. The ARVC penetrance in genotype positive paediatric relatives was 18%. These findings of a high-malignant phenotype in childhood-onset ARVC indicate a need for ARVC family screening at younger age than currently recommended.

Accessibility and interventions of crisis resolution teams: a multicenter study of team practices and team differences in Norway.

BACKGROUND: Components of crisis resolution teams' (CRTs) practices have been defined in recommendations and a fidelity scale, and surveys have reported how team leaders describe CRT practices. However, studies on CRTs have not measured and reported details of the crisis intervention provided to individual service users. The present study aimed to measure how various components of CRT practice were provided to individual service users and differences in practice between CRTs. METHODS: The study was exploratory and part of a prospective multicenter pre-post project on outcome of CRT treatment in Norway. Accessibility and intervention components of 25 CRTs were measured for 959 service users at the first contact after referral and in 3,244 sessions with service users. The data on CRT practice components were analyzed with descriptive statistics and factor analyses, and differences between teams were analyzed using ANOVA and calculating the proportion (intraclass correlation coefficient) of total variance that was due to differences between teams. RESULTS: One-third of the service users had their first session with the CRT the day of referral and another third the following day. Treatment intensity was mean 1.8 sessions the first week, gradually decreasing over subsequent weeks. Three of ten sessions were conducted in the service user's home and six of ten in the team's location. Eight of ten sessions took place during office hours and two of ten in the evening. The CRT provided assessment and psychological interventions to all service users. Family involvement, practical support, and medication were provided to two of ten service users. Between CRTs, significant differences were identified for a substantial proportion of practice components and especially for several aspects of accessibility. Cluster analysis identified two clusters of CRTs with significant differences in accessibility but no significant differences in the use of intervention components. CONCLUSIONS: Measurements of accessibility and interventions provided to individual service users gave a detailed description of CRT practices and differences between teams. Such measurements may be helpful as feedback on clinical practice, for studying and comparing crisis resolution team practices, and in future studies on the association between different outcomes and potential critical elements of crisis interventions.

Similarities and differences between service users' and carers' experiences of crisis resolution teams in Norway: a survey.

BACKGROUND: Crisis resolution team (CRT) care in adult mental health services is intended to provide accessible and flexible short-term, intensive crisis intervention to service users experiencing a mental health crisis and involve their carers (next of kin). Research on users' and especially carers' experiences with CRT care is scarce and is mostly qualitative in nature. METHODS: Altogether, 111 service users and 86 carers from 28 Norwegian CRTs were interviewed with The Service User and Carer Structured Interviews of the CORE Crisis Resolution Team Fidelity Scale Version 2. Their experiences with different aspects of CRT care were reported with descriptive statistics, and differences between service users' and carers' experiences were analyzed with the Mann-Whitney U Test. RESULTS: The service users and carers reported that the CRT care mostly reflected their needs and what they wanted. The experiences of service users and carers were mostly similar, except for significant differences in received information and how the termination of CRT care appeared. Both groups experienced the organization of the CRT care as accessible, with continuity, reliability, and flexibility, but without a high intensity of care. Both groups found the content of the CRT care supportive, sensitive, with a choice of treatment type and a range of interventions beyond medication, but a lack of written treatment plans and discharge plans. Carers were rarely involved in discharge meetings. Regarding the role of CRTs within the care system, both groups agreed upon the lack of facilitation of early discharge from inpatient wards and lack of home treatment, but both groups confirmed some collaboration with other mental health services. CONCLUSION: Service users and carers found that the CRTs were accessible, reliable, flexible, supportive, sensitive, and provided a range of interventions beyond medication. Limitations were lack of a high intensity of care, limited written treatment and discharge plans, limited provision of home treatment, and lack of gatekeeping of acute beds. Both groups experienced the CRT care as mostly similar, but with significant differences regarding involvement in care planning and discharge preparation.

'No service is an island': experiences of collaboration with crisis resolution teams in Norway.

Crisis resolution teams (CRTs) are a community-based service targeting adults experiencing acute mental health crises. The rationale for the development of CRTs is both value and efficacy based, suggesting that CRTs should contribute to the humanizing of mental health services and replace some acute hospital-based services with services in the community. Despite the collaborative nature of CRT work, how professionals from health and social services experience collaboration with CRTs is scantly explored. In the current study, semi-structured focus group interviews with eight different groups of 44 clinicians collaborating with CRTs in Norway were conducted. Data were analyzed using thematic analysis and categorized into four themes: (1) 'The accessible experts', (2) 'A broad and deep expertise', (3) 'Doing it together' and (4) 'Toward a new culture?'. The themes elaborate on issues related to the content and organization of CRT services, emphasizing the need for CRTs to be able to contribute their professional expertise in accessible, flexible and collaborative ways. A diversity in the knowledge base and in how services are organized may pose a challenge in interprofessional mental health crisis collaboration and mutual expectations. The study suggests that a shift toward a value-based and coherent mental health and social system could be a purposeful direction.

Level 1 of Entrustable Professional Activities in adult echocardiography: a position statement from the EACVI regarding the training and competence requirements for selecting and interpreting echocardiographic examinations.

The goal of Level 1 training in echocardiography is to enable the trainee to select echocardiography appropriately for the evaluation of a specific clinical question, and then to interpret the report. It is not the goal of Level 1 training to teach how to perform the examination itself-that is the goal of higher levels of training. However, understanding the principles, indications, and findings of this crucial technique is valuable to many medical professionals including outside cardiology. This should be seen as part of a general understanding of cardiac imaging modalities. The purpose of this position statement is to define the scope and outline the general requirements for Level 1 training and competence in echocardiography. Moreover, the document aims to make a clear distinction between Level 1 competence in echocardiography and focus cardiac ultrasound (FoCUS).

The Prognostic Value of Right Atrial Strain Imaging in Patients with Precapillary Pulmonary Hypertension.

BACKGROUND: Right ventricular (RV) failure in patients with pulmonary hypertension (PH) is associated with unfavorable clinical events and a poor prognosis. Elevation of right atrial (RA) pressure is established as a marker for RV failure. However, the additive prognostic value of RA mechanical function is unclear. METHODS: The authors tested the hypothesis that RA function by strain echocardiography has prognostic usefulness by studying 165 consecutive patients with precapillary PH defined invasively: mean pulmonary artery pressure ≥ 25 mm Hg and pulmonary capillary wedge pressure < 15 mm Hg. Speckle-tracking strain analyses of the right atrium and right ventricle were performed, along with routine measures. Peak RA strain values from six segments using generic speckle-tracking software were averaged to RA peak longitudinal strain, representing RA global reservoir function. The primary end point was all-cause mortality during 5 years of follow-up. RA strain was similarly analyzed in a control group of 16 normal subjects for comparison. RESULTS: There were 151 patients with PH (mean age, 55 ± 16 years; 73% women; mean World Health Organization functional class, 2.6 ± 0.6), after 14 exclusions (three with atrial septal defects and 11 with left ventricular ejection fractions < 50%). RA strain measurement was feasible in 93% of patients and RV strain measurement in 88%. RA peak longitudinal strain was significantly reduced in patients with PH compared with control subjects, as expected (P < .001). During 5-year follow-up, 73 patients (48%) died. Patients with RA peak strain in the lowest quartile (<25%) had a significant risk for death (P = .006), even after correcting for confounding variables. RA strain was independently associated with survival in multivariate analysis (P = .039) and had additive prognostic value to RV strain (log-rank P = .01) in subgroup analysis. CONCLUSIONS: RA peak longitudinal strain had additive prognostic usefulness to other clinical measures, including RV strain, RA area, and RA pressure, in patients with PH. RA mechanical function by strain imaging has potential for clinical applications in patients with PH.

Exercise is Associated With Impaired Left Ventricular Systolic Function in Patients With Lamin A/C Genotype.

Background Lamin A/C cardiomyopathy is a malignant and highly penetrant inheritable cardiomyopathy. Competitive sports have been associated with adverse events in these patients, but data on recreational exercise are lacking. We aimed to explore associations between exercise exposure and disease severity in patients with lamin A/C genotype. Methods and Results Lamin A/C genotype positive patients answered a questionnaire on exercise habits from age 7 years until genetic diagnosis. We recorded exercise hours >3 metabolic equivalents and calculated cumulative lifetime exercise. Patients were grouped in active or sedate based on lifetime exercise hours above or below median. We performed echocardiography, 12-lead ECG, Holter monitoring, and biomarkers including NT-proBNP (N-terminal pro-B-type natriuretic peptide). We defined left ventricular ejection fraction <45% as a clinically significant impairment of left ventricular function. We included 69 patients (age 42±14 years, 41% probands, 46% women) with median lifetime exercise 4160 (interquartile range 1041-6924) hours. Active patients were more frequently probands (53% versus 29%, P=0.04), had lower left ventricular ejection fraction (43±13% versus 51±11%, P=0.006), and higher NT-proBNP (78 [interquartile range 32-219] pmol/L versus 30 [interquartile range 13-64] pmol/L, P=0.03) compared with sedate, while age did not differ (45±13 years versus 40±16 years, P=0.16). The decrease in left ventricular ejection fraction per tertile increment in lifetime exercise was 4% (95% CI -7% to -0.4%, P=0.03), adjusted for age and sex and accounting for dependence within families. Left ventricular ejection fraction <45% was observed at a younger age in active patients (log rank P=0.007). Conclusions Active lamin A/C patients had worse systolic function compared with sedate which occurred at younger age. Our findings may improve exercise recommendations in patients with lamin A/C.

Global Left Ventricular Strain at Presentation Is Associated with Subsequent Recovery in Patients with Peripartum Cardiomyopathy.

BACKGROUND: Peripartum cardiomyopathy (PPCM) is a serious complication of pregnancy associated with variable degrees of left ventricular (LV) recovery. The aim of this study was to test the hypothesis that global LV strain at presentation has prognostic value in patients with PPCM. METHODS: One hundred patients with PPCM aged 30 ± 6 years were enrolled in the multicenter Investigation in Pregnancy Associated Cardiomyopathy study along with 21 normal female control subjects. Speckle-tracking global longitudinal strain (GLS) and global circumferential strain (GCS) analysis was performed. The predefined primary combined outcome variable was death, transplantation, LV assist device implantation, or evidence of persistent LV dysfunction (LV ejection fraction [LVEF] < 50%) at 1 year. RESULTS: GLS measurement was feasible in 110 subjects: 89 of 90 patients with PPCM (99%) with echocardiographic data and all 21 control subjects. Of 84 patients (94%) with 1-year follow-up, 21 (25%) had unfavorable primary outcomes: four LV assist device placements, two deaths, and 15 patients with persistent LV dysfunction. GLS at presentation with a cutoff of 10.6% (absolute value) was specifically associated with the subsequent primary outcome with 75% sensitivity and 95% specificity. GCS at presentation with a cutoff of 10.1% was associated with the primary outcome with 78% sensitivity and 84% specificity. GLS and GCS remained significantly associated with outcomes after adjusting for LVEF (GLS odds ratio, 2.07; P < .001; GCS odds ratio, 1.37; P = .005). GLS was significantly additive to LVEF (C statistic = 0.76-0.91, net reclassification improvement = 1.32, P < .001). CONCLUSIONS: GLS and GCS in patients with PPCM at presentation were associated with subsequent clinical outcomes, including death, LV assist device implantation, and evidence of persistent LV dysfunction. Strain measures may add prognostic information over LVEF for risk stratification.

Lamin A/C cardiomyopathy: young onset, high penetrance, and frequent need for heart transplantation.

Aims: Lamin A/C (LMNA) mutations cause familial dilated cardiomyopathy (DCM) with frequent conduction blocks and arrhythmias. We explored the prevalence, cardiac penetrance, and expressivity of LMNA mutations among familial DCM in Norway. Furthermore, we explored the risk factors and the outcomes in LMNA patients. Methods and results: During 2003-15, genetic testing was performed in patients referred for familial DCM. LMNA genotype-positive subjects were examined by electrocardiography, Holter monitoring, cardiac magnetic resonance imaging, and echocardiography. A positive cardiac phenotype was defined as the presence of atrioventricular (AV) block, atrial fibrillation/flutter (AF), ventricular tachycardia (VT), and/or echocardiographic DCM. Heart transplantation was recorded and compared with non-ischaemic DCM of other origin. Of 561 unrelated familial DCM probands, 35 (6.2%) had an LMNA mutation. Family screening diagnosed an additional 93 LMNA genotype-positive family members. We clinically followed up 79 LMNA genotype-positive [age 42 ± 16 years, ejection fraction (EF) 45 ± 13%], including 44 (56%) with VT. Asymptomatic LMNA genotype-positive family members (age 31 ± 15 years) had a 9% annual incidence of a newly documented cardiac phenotype and 61% (19/31) of cardiac penetrance during 4.4 ± 2.9 years of follow-up. Ten (32%) had AV block, 7 (23%) AF, and 12 (39%) non-sustained VT. Heart transplantation was performed in 15 of 79 (19%) LMNA patients during 7.8 ± 6.3 years of follow-up. Conclusion: LMNA mutation prevalence was 6.2% of familial DCM in Norway. Cardiac penetrance was high in young asymptomatic LMNA genotype-positive family members with frequent AV block and VT, highlighting the importance of early family screening and cardiological follow-up. Nearly 20% of the LMNA patients required heart transplantation.

Geometry as a Confounder When Assessing Ventricular Systolic Function: Comparison Between Ejection Fraction and Strain.

BACKGROUND: Preserved left ventricular (LV) ejection fraction (EF) and reduced myocardial strain are reported in patients with hypertrophic cardiomyopathy, ischemic heart disease, diabetes mellitus, and more. OBJECTIVES: The authors performed a combined mathematical and echocardiographic study to understand the inconsistencies between EF and strains. METHODS: An analytical equation showing the relationship between EF and the 4 parameters, global longitudinal strain (GLS), global circumferential strain (GCS), wall thickness, and short-axis diameter, was derived from an elliptical LV model. The equation was validated by measuring the 4 parameters by echocardiography in 100 subjects with EF ranging from 16% to 72% and comparing model-predicted EF with measured EF. The effect of the different parameters on EF was explored in the model and compared with findings in the patients. RESULTS: Calculated EF had very good agreement with measured EF (r = 0.95). The model showed that GCS contributes more than twice as much to EF than GLS. A significant reduction of GLS could be compensated by a small increase of GCS or wall thickness or reduced diameter. The model further demonstrated how EF can be maintained in ventricles with increased wall thickness or reduced diameter, despite reductions in both longitudinal and circumferential shortening. This was consistent with similar EF in 20 control subjects and 20 hypertrophic cardiomyopathy patients with increased wall thickness and reductions in both circumferential and longitudinal shortening (all p < 0.01). CONCLUSIONS: Reduced deformation despite preserved EF can be explained through geometric factors. Due to geometric confounders, strain better reflects systolic function in patients with preserved EF.

The systolic paradox in hypertrophic cardiomyopathy.

OBJECTIVE: We explored cardiac volumes and the effects on systolic function in hypertrophic cardiomyopathy (HCM) patients with left ventricular hypertrophy (HCM LVH+) and genotype-positive patients without left ventricular hypertrophy (HCM LVH-). METHODS: We included 180 HCM LVH+, 100 HCM LVH- patients and 80 healthy individuals. End-Diastolic Volume Index (EDVI), End-Systolic Volume Index (ESVI) and ejection fraction (EF) were assessed by echocardiography. Left ventricular (LV) global longitudinal strain (GLS) was measured by speckle tracking echocardiography. RESULTS: EDVI and ESVI were significantly smaller in HCM LVH+ compared with HCM LVH- patients (41±14 mL/m2 vs 49±13 mL/m2 and 16±7 mL/m2 vs 19±6 mL/m2, respectively, both p<0.001) and in healthy individuals (41±14 mL/m2 vs 57±14 mL/m2 and 16±7 mL/m2 vs 23±9 mL/m2, respectively, both p<0.001). HCM LVH- patients had significantly lower EDVI and ESVI compared with healthy individuals (49±13 mL/m2 vs 57±14 mL/m2 and 19±6 mL/m2 vs 23±9 mL/m2, both p<0.001). EF was similar (61%±7% vs 60%±8% vs 61%±6%, p=0.43) in the HCM LVH+, HCM LVH- and healthy individuals, despite significantly worse GLS in the HCM LVH+ (-16.4%±3.7% vs -21.3%±2.4% vs -22.3%±3.7%, p<0.001). GLS was worse in the HCM LVH- compared with healthy individuals in pairwise comparison (p=0.001). Decrease in ESVI was closely related to EF in HCM LVH+ and HCM LVH- (R=0.45, p<0.001 and R=0.43, p<0.001) as expected, but there was no relationship with GLS (R=0.02, p=0.77 and R=0.11, p=0.31). Increased maximal wall thickness (MWT) correlated significantly with worse GLS (R=0.58, p<0.001), but not with EF (R=0.018, p=0.30) in the HCM LVH+ patients. CONCLUSION: HCM LVH+ had smaller cardiac volumes that could explain the preserved EF, despite worse GLS that was closely related to MWT. HCM LVH- had reduced cardiac volumes and subtle changes in GLS compared with healthy individuals, indicating a continuum of both volumetric and systolic changes present before increased MWT.